Shaekirk - two words, 'face mask.' I too, sneeze a lot when cleaning units.

For inside doors, this is time consuming once a year, but makes cleaning a breeze afterwards.

Grab the Pledge (yes, the spray furniture polish) and do your hallway doors, headers, the walls and such. Might I suggest using a webster first to clean the tops of sprinkler pipes and cobwebs before polishing the doors. Work from the top down on everything. Spray the cloth, NOT the doors and be careful about inadvertently overspraying and waxing the floors. You don't want to slip.

The doors will sparkle and dust brushes off easily after one application. We also clean each door inside and out as a unit is vacated. Usually we start with a fresh webster and it takes on a form of its own after cleaning a few units.

Using brushes usually leaves brush marks of cleaned areas, so best thing we do is use a cloth on the outside of the hallway doors.

For the hallway floors, an old fashioned dust mop works nicely and we mop as needed which as you know varies dependent upon foot traffic.

Outside doors we too pray for a nice sideways rain storm, but you can't count on Mother Nature to do the work. Each May we bring out the power washer and do a building or so a day. We wait until May to be sure we won't have a light shower spot up what dust may be there so the cleaning job lasts longer.

The power washer has a tube to drop into a bucket for incorporating into the spray nozzle. We use this for a bucket with Dawn liquid dishwashing soap in it. It is the best thing to get rid of the grit and it won't harm your concrete or asphalt driveways.

With a power washer you do need to watch the angle & intensity of the spray. You want to stand back a bit and make sure you're not spraying up into the units over the top of the rollup and under the header boards.

We do follow up by washing down the driveways, in our case it is asphalt. All the dirt from the buildings is now there and we want the whole place to shine when we're done.

To answer Drew's post - "What do you think HAS to be done regularly--whether or not you like, but for the sake of keeping customers coming back?"
Maintain EVERYTHING!

Our favorite part of meeting each new customer is hearing, "Wow, this place is brand new, it's so clean, (or shiny or some other adjective)." We are then able to respond "Thank you, actually this part of our facility is over ten years old. The second phase is over seven years old." or something along these lines. I confess, we do feel a lot of pride from those comments.

My least favorite task is repainting the red curbs. I finally located a man who does them all extremely cost effectively. That's how I solved that unpleasant chore.